Drones occupy a highly visible place in contemporary American farm and livestock management.  But their emerging role in pest control in the nation’s greenhouses and nurseries, while less heralded, may be just as important.  Relatively small insect and bacterial infestations can wreak havoc on the trees, shrubs, plants and flowers that have become staples of America’s ever-expanding and highly lucrative landscape industry.  Many developers have learned the hard way that traditional pesticide spraying methods – conducted with manned aircraft or with field crews operating on foot – aren’t sufficiently targeted to preserve and protect the floral aesthetics and health of their properties.

For the past four years, Stanton Gill, principal extension agent in entomology at the University of Maryland, has been experimenting with drones as a low-cost tool for spraying pesticides to deter insect and bacterial attacks on popular plants and flowers like chrysanthemums. He’s beginning to make real headway and companies throughout the state and beyond have begun to take notice.

Back in 2019, Gill received a three-year grant from the USDA to test his precision spraying system.  The system relies on a single DJI Agras MG-1P drone outfitted with a 2.5 gallon spray tank.  It’s a surprisingly simple but effective and extremely low-cost system, saving time and man hours alike.

For Gill, the main challenge was getting government support for his tests in today’s highly regulated farm management industry.  In addition to sign-off from the FAA, his team needed to secure approval from the Department of Homeland Security and from the state Department of Agriculture, which was concerned about the types of pesticides Gill planned to use. Gill also needed to find an insurer willing to underwrite the project.

It’s been worth the wait.  In early tests, his DJI drone has outperformed traditional pesticide spraying methods, which typically require large clumsy hoses to be dragged through the fields, not only disturbing the soil but invariably over-spraying while still missing important areas of coverage. Drones, he showed, can size up just how much pesticide is needed while leaving soil and crop untouched.  In the case of large outdoor fields, drones are especially useful for reaching areas close to tree canopy that traditional pesticide-spraying aircraft typically avoid as too risky.

The cost advantages of drones are obvious.  A single drone operator can cover 16 acres of chrysanthemums in three hours, with a half hour each for equipment preparation and pack-up.  At $150 per hour, the entire spray operation cost Gill’s team just $600, a real bargain, compared to the expense of a manned aircraft and crew spraying overhead in a less targeted and efficient operation.

Most of Gill’s experiments to date have dealt with large outdoor farms with prospective infestations of caterpillars and earworms primarily.  Indoor nurseries pose a separate challenge.  For one thing the pests, which often remain in a quasi-larval state, can be far more difficult to detect – and target.  In addition, indoor greenhouse spaces demand much greater drone maneuverability, with a combination of unmanned and remote piloting required.  Gill plans to trial a drone spraying operation during the summer and fall of 2022, possibly deploying a smaller drone appropriate for the confined setting.  His test results – eagerly anticipated by industry – will be ready for dissemination in early 2023.